The responses of soil respiration to simulated nitrogen deposition were investigated through in-suit spray with four rising nitrogen concentration levels: control (CK, 0 kgN·hm^-2a^-1), low nitrogen (T₅₀, 50 kgN·hm^-2a^-1), medium nitrogen (T₁₀₀, 100 kgN·hm^-2a^-1) and high nitrogen (T₁₅₀, 150 kgN·hm^-2a^-1). This study was conducted in an evergreen broad-leaved forest in Jinyun mountain, Chongqing City. Results showed that the CK,T₅₀,T₁₀₀ and soil respiration rates were(4.31±1.14),(3.42±0.74),(2.81±0.38) and (2.49±0.32) μmol·m^-2s^-1, respectively, indicating that nitrogen deposition treatments significantly reduced soil respiration rates (P<0.05).The relationships between soil respiration rates under different nitrogen treatments and soil temperature, and water contents at depths of 5 and 10 cm were analyzed. A remarkable positive correlation was found between soil respiration rates and soil temperature(P<0.01). The temperature sensitivity coefficients(Q₁₀ value)at 5 cm depth were 2.07(CK),1.81(T₅₀),1.62(T₅₀) and 1.54(T₅₀)respectively, and at 10 cm depth were 2.11(CK),1.83(T₅₀),21.63(T₁₀₀) and 1.55(T₁₅₀)respectively, which demonstrated that the sensitivity of soil respiration to soil temperature was restrained by nitrogen deposition. However, there was no obvious correlation between soil respiration rate and soil moisture.

In order to understand the recruitment mechanism and recovery process of Betula albosinensis forest, an investigation was conducted in B. albosinensis forest of Taibai Mountain, Qinling Mountains. Based on data collected from 1-hm² plots, the spatial pattern and spatial correlation of B. albosinensis populations at different developmental stages were analyzed at multiple scales by the O-ring functions of single variable and double variables. The results showed that the natural recruitment of B. ablosinensis were scarce, however more saplings were recruited in stand with artificial disturbances. B. albosinensis saplings were significantly clustered together in a range from 0 to 10 m, but the clustered pattern intensities decreased with increasing age so that large trees presented a stochastic spatial distribution at most scales. As to the spatial correlations, there was a negative correlation between saplings and large trees at scale from 0 to 15 m, whereas no significant correlations were observed between saplings and medium trees as well as medium trees and large trees in most scales. Disturbances drove the regeneration dynamics of most closed-canopy forests by creating opportunities for the establishment of new individuals through canopy opening. The findings suggest that as an intolerant species, natural B. albosinensis population requires disturbed microsites and canopy openings for regeneration. The recruitment of B. ablosinensis offspring was restricted not only by interspecific competition but also by intraspecific competition due to their shade sensitivity. Thus, moderate severity of disturbance created by selective cut would be useful for B. albosinensis recruitment by releasing space and reducing forest litters cover. The spatial pattern of B. albosinensis population depends on their biological characteristics, intraspecific relationship and environmental heterogeneity. Naturally, the aggregation of different cohorts in space and time might be the strategy of B. ablosinensis population stability.

Phyllostachys praecox plantations with various ages and the neighboring paddy field (served as control) were selected for analysis of soil acidity, the soil extractable Al content and the bamboo Al content. Results showed that the soil was severely acidified in P. praecox stands after shifted from the paddy field. The intensive management increased soil organic matter content up to 64.2 g·kg^-1 that was 50% higher than in the control. Soil extractable Al content increased significantly with the cultivation duration of bamboo. The highest content of 8-hydroxyquinoline extractable Al was 108.0 mg· kg^-1 that was 10 times as the control and acetic acid extractable Al content was 235.4 mg·kg^-1 that was 4 times as the control. The Al content in the bamboo roots increased with the cultivation duration. However, Al contents in the bamboo rhizomes, stems and leaves were the opposite, suggesting there was a damage of nutrient transport in bamboo due to the Al toxicity. Accordingly, the increased soil phytotoxic and bioavailable Al content along with the severe soil acidification did harm to the bamboo growth under the intensive management.

A simulated nitrogen deposition experiment in the field was conducted in a Eucalyptus grandis stand for 14 months. The levels of nitrogen deposition were 0(CK), 5 (L), 15 (M) and 30 (H) g N m^-2·a^-1 respectively. The soil respiration was measured by infrared gas analyzers, and then NH₄NO₃ was added into N-treated plots in the last third of each month. Results showed that: The soil respiration in E. grandis forest displayed an obvious seasonal pattern in the rainy area of western China. The lowest rate occurred in January and the highest rate In July for the all treatments. After 3 months of nitrogen deposition treatment, the soil respiration was promoted significantly, especially in July, the respiration rate of treatment L, M, and H was 8.80%, 22.62%, 32.41% higher than CK, respectively. CO₂ releases from the soil of E. grandis forest were increased by 11.93% to 30.82% after nitrogen deposition treatment. The average soil respiration rate in 24 hour was in an order of CKR_s= aW+b,R_s= ae^bt). The Q₁₀ values were increased correspondingly with the N addition. The result indicated that nitrogen deposition might increase temperature sensitivity of soil respiration.

In this paper, the annual air temperature, sunshine duration, soil temperature, precipitation, soil freeze-thaw and river flow were analyzed based on data of monitoring meteorology, soil freezing and thawing, triangle weir hydrograph and volume from 2002 to 2011 in Pailugou watershed of Qilian Mountains. The results showed that: Average annual temperature was 1.7℃, and annual sunshine duration was 127.1 h. The soil temperature was 3.3℃ on the soil surface, 2.3℃ at 5, 10, and 15 cm depth, 2.4℃ at 20 and 40 cm depth. The soil freezing began around 11^th of October; the soil ablation finish was around 17^th of July. Frozen period was 278 days, accounted for 76.16% of a year. The rate of frozen soil thickness augment was about 1.22 cm ·d^-1 before the 10^th of December, then it reduced to 0.78 cm ·d^-1, and reached the minimum to 20^th of March, at which the thickness of frozen soil reached to the maximum, and the average maximum thickness was 159.6 cm; Soil thawing started around 2^nd of April with the increasing rate, and ended around 17^th of July, and the average melting rate was 1.47 cm ·d^-1. The regression model for S (runoff) and P (precipitation) was 2.936P + 9.587 (R²=0.742 6), and the regression model for S (runoff) and frozen-thaw thickness of soil was -10.361F_d + 1 388.498 (R²=0.701 7).

A pot experiment in greenhouse was conducted to investigate the effects of 0 (control), 120, 240 and 360 mmol·L^-1 NaCl treatments on growth, biomass accumulation and allocation, and photosynthetic gas exchange parameters of Elaeagnus angustifolia seedlings, and the correlations between growth parameters and photosynthetic parameters were also analyzed. The results showed that: 1) net height increment, branch number per plant, other growth parameters and biomass accumulation of NaCl-stressed seedlings were all lower or significantly lower than those of the control. With the salt concentration elevated, the above-mentioned growth parameters exhibited a decreasing trend, whereas the root-shoot ratio and root biomass allocation ratio both increased consecutively. 2) With the salt stress aggravated, net photosynthetic rate (P_n), stomatal conductance (G_s), intercellular CO₂ content (C_i) and transpiration rate (Tr) generally exhibited a decreasing trend, while stomatal limitation value (L_s) and water use efficiency (WUE) had an increasing trend. P_n, G_s, C_i and Tr of 360 mmol ·L^-1 NaCl-treated seedlings were only 57.2%, 22.7%, 62.8%, 38.1% of the control, respectively, whereas the L_s and WUE of the same stressed seedlings were 2.0 and 1.5 times higher than that of the control. 3) Plant height, various leaf growth parameters, whole-plant biomass accumulation and various photosynthetic parameters had all extremely significant and negative correlations with salt stress intensity. Various leaf photosynthetic parameters were significantly or extremely significantly correlated with leaf growth parameters, and there were also significant or extremely significant correlations between parameters of leaf growth and photosynthesis and parameters of biomass accumulation and allocation. In conclusion, our findings suggested that growth and photosynthetic physiology of E. angustifolia seedlings were directly inhibited by NaCl stress, and there were also interactions between leaf photosynthetic capacity and leaf growth parameters, all these factors ultimately brought about a decrease in plant biomass accumulation.

A greenhouse pot experiment was conducted to investigate the impact of AM fungi inoculation on the soil micro-eco in the rhizosphere of beach plum (Prunus maritima) seedlings. We selected three species of AM fungi, Glomus mosseae, G. etunicatum, and G. diaphanum, to infect the seedlings, and determined the infection rate of AM fungi, plant biomass, number of microorganisms in the rhizosphere, soil pH, enzyme activity of soil, N and P nutrients in the rhizosphere. The results showed that the all three AM fungi formed mycorrhizal compound with the host plant. G. mosseae and G. etunicatum had higher infection rate than G. diaphanum, and their infection rates were 50.4% and 48.3%, respectively. The biomass of seedlings infected by the two AM fungi was 1.74 and 1.73 times of the control, respectively. AM mycorrhizae impacted microbial populations around the roots, and the number of bacteria, actinomycetes and nitrogen-fixing bacteria on the root surface increased significantly. AM fungi accelerated the activities of phosphatase, urease, and proteinase in soil rhizosphere, and the activities of these enzymes were positively correlated with the infection rate of AM fungi. AM fungi decreased the pH value of rhizosphere, and the pH value was correlated with the infection rate of AM fungi negatively. The available N and P were accumulated in the rhizosphere of the seedlings inoculated with AM fungi, and the accumulation was correlated with the infection rate of AM fungi remarkably. Among the three Glomus species, G. mosseae and G. etunicatum were more effective. In summary, AM formation improved the micro-ecological environment of beach plum seedlings and increased soil fertility in the rhizosphere, but the ecological effects varied dependent on the species of AM fungi.

To illustrate the effect of ground cover on early regeneration, seed germination and seedling growth of Pinus tabulaeformis under different sowing patterns were measured, with different litter thickness and different litter aqueous extracts treatments. The results showed that sowing patterns had significant effects on the seed germination and seedling growth of P. tabulaeformis, and the germination rate was in an order of clearing shrubs herbs and litters > clearing herbs and litters > clearing shrubs and litters > clearing shrubs and herbs, indicating that litter was the major factor influencing the seed germination and seedling growth of P. tabulaeformis. The height, the basal diameter, the root and stem biomass of the seedlings under clearing shrubs herbs and litters and clearing shrubs and herbs were higher than other sowing patterns. The 1 cm and 2 cm thickness litters had no influence on the seed germination of P. tabulaeformis, but the 3 cm thickness litters and paving litters before sowing significantly decreased the germination rate of P. tabulaeformis seed and the beginning time of germination. The litter water extract had no significant influence on P. tabulaeformis seed germination and the early growth of seedlings. These results indicated litter affected the P. tabulaeformis early regeneration by physical obstacles, thus reasonable cleaning up ground cover can promote the natural regeneration of P. tabulaeformis plantation.

Although a factorial mating design has been extensively applied in forest breeding programs, there exist some problems with the design in calculating the estimates of genetic parameters and some statistics, especially when the experimental data are unbalanced. A newly developed Windows-based software (WinNC2), for calculating model parameters of the genetic factorial mating design, can not only deal with balanced data but also with unbalanced data. For three different factorial mating designs, the software estimates the general and special combining abilities of parents and other fixed effects with the restricted linear model, and calculates the genetic variance components and further the heritabilities with the random effect model. In the mean time, WinNC2 can provide standard errors and statistic tests for each parameter estimate. Furthermore, WinNC2 can also present the genetic correlation coefficient between any two traits at each level of paternal, maternal, and their interaction effects. In summary, WinNC2 is a user-friendly computing tool for forest breeders to analyze genetic models of factorial mating designs.

In order to understand the underline mechanism for inducing normal flowering efficiently by HSP ∷ FT construct on forest trees, transgenic poplar plants (Populus tremula × P. tremuloides) containing HSP ∷ FT 1 were used as the experimental material to investigate factors affecting FT gene expression to induce precociously flowering of poplar by heat shock treatment in this paper. The results showed that the factors, such as transgenic lines and ramets, plant size and age, heat shock temperature, heat induction duration, and environment temperature, all affected FT gene expression to induce flowering of transgenic plants. Different transgenic lines and different ramets in the same line varied significantly in the induced flowering. Plants with a height lower than 30 cm failed to flower. Flowering frequency increased with increasing height of plants. Heat shock temperature affected initial flowering time, flowering frequency and normal catkin yields. The optimum temperature was 40℃. Flowering of transgenic plants by heat shock was mainly influenced by daily heat induction hours at early stages and by heat induction duration at later stages. The continue heat treatment for more than 3 weeks was efficient to induce flowering. It was beneficial to flowering induction and normal catkin development if transgenic plants grew at lower environment temperature before heat treatment.

In this study, Xenopus laevis oocytes were used to test the functional characterization of our previously cloned HbPIP 1 and HbPIP 2 aquaporin genes from rubber trees (Hevea brasiliensis). The result showed that HbPIP 1 had the function of transmembrane water transport however HbPIP 2 has not. We therefore infer that HbPIP 1 is involved in the mechanism of Ethrel-induced latex promotion. An Ethrel sensitive rubber clone PR107 was selected as the plant material. The gene expression profiles of HbPIP 1 at both transcript level and translation level were examined by RT-qPCR and Western blot to investigate their link with the effect of Ethrel on latex flow duration, latex volume, dry rubber content (DRC) and total solids content (TSC). It was found that the expression of HbPIP 1 in latex, bark and xylem was higher than that in petioles and blades of various periods. The expression of HbPIP 1 in PR107 latex presented an increase trend with the Ethrel treatment duration, while it was down-regulated in the bark. This expression might facilitate the water transport into rubber laticifers and therefore can decrease latex DRC and TSC, prolong latex flow and enhance the latex yield.

Magnolia sprengeri is an important ornamental plant species. In this study 8 ISSR primers were used to examine the genetic diversity and genetic structure of 9 natural M.sprengeri populations which included 71 individuals, collected from Shaanxi, Hubei, Chongqing of China which belong to the main distribution area.A total of 207 valid loci were obtained, of which 195 were exhibited polymorphism. The percentage of polymorphic bands (PPB) were 94.20% at species level and 43.64% at population level, and the mean diversity estimated with Nei's index (H) and Shannon's information index (I) was 0.171 9 and 0.288 2 at species level, and 0.128 4 and 0.198 8 at population level, respectively. Analysis of molecular variance (AMOVA) demonstrated that the proportion of genetic variation was 68.10% (P<0.001) within population, and 31.90% (P<0.001)among populations. The differential index (G_ST) among the populations was 0.257 0. All these results indicated that there was a significant genetic differentiation both within and among the populations. The gene flow (N_m) among populations was 1.445 6 and the genetic distance among 9 populations was 0.040 0. The UPGMA cluster analysis divided the 9 populations into 3 major groups, which was consistent well with the geographical distribution and floral characters of most of the populations except for some transitional populations.

It is important to model stand volume of Chinese fir(Cunninghamia lanceolata)for improving forest management and revealing forest growth law. According to the different simulation objects, stand volume of Chinese fir can be predicted from tree level and stand level. In this study, the two level models were combined by forecast combination. Forecast combination combines information from different models, disperse errors from different models, and then improve forecast performance. In this paper, weights of different models in the forecast combine model were calculated by optimal weight. Based on the periodic data of the Chinese fir in Jiangxi Province, forecast combination was used to estimate Chinese fir stand volume from tree-level model, and stand-level model. The results showed that the forecast combination for predicting Chinese fir stand volume outperformed over tree-level model, and stand-level model respectively. It also improved the compatibility of Chinese fir stand volume growth models from different levels of models and provided a method for integration of Chinese fir stand volume.

Many remote sensing data have been applied to estimate forest above ground carbon storage(AGCS), but the estimation accuracy is varying. The capability of remotely sensed CBERS-02B CCD data for tropical and subtropical AGCS estimation is unknown. In this paper, with Dongguan forest region as a case study area, the CBERS-02B CCD data, along with the field survey data, were used to examine the relationship between forest biomass and band reflectance, vegetation indices, and image texture. It was found image texture performed the best in biomass estimation. When the band reflectance, vegetation indices, and image texture were combined in stepwise multiple regressions for biomass estimation, the adjustment coefficient R² was 0.53, root mean square error was 15.66, and P-level was less than 0.05, indicating the significance of the model. The results also showed that the shift of near-infrared band of the CBERS-02B CCD had negative effect on biomass estimation, but the integration of band reflectance, vegetation indices, and image texture can improve the capability of CBERS-02B CCD data for AGCS estimation, because the integration can reduce limitation and improve the complementarity. Moreover, the spatial distribution of AGCS mapping by CBERS-02B CCD data is similar with the actual distribution. We concluded that CBERS data are promising for estimating subtropical forest biomass.

Clostera anastomosis and C. restitura are similar in adult morphology, living habits and harm way and with overlapping 2,thus they are usually hard to be distinguished form each other. In order to accurately clarify their distribution and forecast their population dynamics, the morphological differences of egg, larva, pupae and adult were compared, and the distribution and biological characters were investigated. By amplifying part of mitochondria COⅠ gene, the evolutionary relationship between them was analysed.

In this study, three parasitoid insect species were applied for controlling Apriona swainsoni (Longhorn beetle). Sclerodermus pupariae and S. guani (Hymenoptera: Bethylidae) were released to A.swainsoni young larvae (1st-3rd instar) with a 5 ：1 ratio, and Dastarcus helophoroides (Coleoptera: Bothrideridae) in A.swainsoni middle-aged to mature larval and pupal stages. The results showed that the average decline of the young larvae population was by 14.84% and 12.57% respectively after releasing S. pupariae and S. guani in 25 days. When releasing adults and eggs of D. helophoroides with parasitoid-host numbers ratio 3 ：1 and 10 ：1 respectively, the mean decline rate of the longhorn beetle larvae population was by 46.50% and 38.63% in 30 days; and the average decline rate was 60.00% and 52.67% respectively in 60 days. Based on the data of the controlling effects by cutting and splitting the tested trees, four equations were built to evaluate the actual parasitism rate of D. helophoroides, and among them the quadratic function showed the highest correlation coefficient. Additionally, an investigation on the sustainable control impact was carried out for three years after the parasitoids were released and the result showed that D. helophoroides exerted a sustainable control effect on A. swainsoni. The present study indicates that the three parasitoids could be used to effectively control the longhorn beetle.

Diversity of endophytic fungi in trees is a key to tree health and interaction between trees and environment. Operational taxonomic units based on molecular DNA barconding an important role in disclosing microbiological diversity. Based on criteria and techniques of DNA barcoding approaches, a validation database on ITS sequences of Botryosphaeria genus and its related fungi downloaded from public nucleotide databases in NCBI, was constructed for determining the strains from endophytes in poplars in Beijing area, along with their ITS amplification and phylogenetic relationship analysis. The results showed that there were three populations of Botryosphaeria species parasitic in poplars as endophytes,B. dothidea, B. rhodina and B. parva. Strains of each population had genetica diversity. The approaches and results, presented in this paper,would contribute to a comprehensive understanding endophyte diversity in poplars and promoting researches on relationships between poplar hosts and Botryosphaeria pathogen as well as poplar canker fungal pathagenesis and control.

According to an experimental design in our previous study, fuelbeds were constructed with varied fuel moisture, loading and depth of Korean pine (Pinus koraiensis) needles collected from Korean pine plantations. Totally 87 experimental fires with these fuelbeds were burned in laboratory under different wind conditions. The results showed that wind factor was in 1.24-14.51 when wind speed was in 0.9-4.6 m ·s^-1. The existing models of wind factor are not applicable for Korean pine needles. The model parameter rationalization displayed that the power function model was better than the exponential function model and the multi-sector model was better than the single factor model. Packing ratio and fuel moisture significantly influenced wind factor and their relative error reduction ratio was from 3.7% to 8.2% and 2.9% to 5.4%, Respectively. The effect of fuel loading and fuelbed depth on wind factor was not significant. The wind factor model established with wind speed and packing ratio as predictive variables can account for 45.3% variance of wind factor with mean absolute error of 1.727 and mean relative error less than 28%. Model accuracies were significantly improved when established by packing ratio and fuel moisture with MAE of 1.03 and 75.6% of variance of wind factor explained.

A new algorithm for calculating moisture content (MC) by X-ray scanning was deduced and studied in this paper. Firstly, the principle of the X-ray measuring wood density was presented. Secondly, the volume density of wood components(cell wall material and water)under volume change were quantitatively analyzed based on the concept of volume density in the porous materials. And then the formulas for calculating the MC were deduced with the fiber saturation point (FSP) as demarcation line. Finally, taking Chinese fir(Cunninghamia lanceolata)as the experimental material, the density variation with drying time was measured by X-ray scanning during wood drying process. Based on these data, the MC distribution was calculated by Cai method and volume density method, at the same time, taking slicing method as control group, the results from this three method were compared. The results showed that there were no significant differences between volume density method and slicing method in the entire range of MC. When MC was above FSP, the MC distribution based on Cai method was significantly different with the slicing method, when MC was lower than FSP, there were no significant differences between these two methods. It was suggested that the volume density method was reasonable, which could provide an accurate method for calculating MC distribution during wood drying via X-ray scanning method.

The untreated and thermo-treated Phyllostachys edulis and Bambusa emeiensis bamboo fibrous veneer, which made with the dotted and/or linear shaped fiber separation technology on the semicircular bamboo tube, were reconstructed to form bamboo-based fiber composites with phenolic-formaldehyde adhesive. The physical and decay resistance properties were evaluated, and compared with the traditional bamboo bundle scrimber. The results showed that: Bamboo-based fiber composites showed superior performance than that of bamboo bundle scrimber.Bamboo-based fiber composites made from Bambusa emeiensis had better performances than that made from Phyllostachys edulis. Thermo-treatment would improve the properties of thickness swell, mould proof and so on, but decrease the horizontal shear strength. The bamboo fibrous veneer composed of interlaced fiber bundle was manufactured directly from semicircular bamboo tube without special removing the outer and inner layer of bamboo. The process was easier and the production efficiency was higher compared with traditional bamboo bundle.

This paper introduces a novel technology for modification of low-density fast-growing wood veneer, softening at high temperature with saturated steam and transverse compression in a sealed environment. It exploits the viscoelastic characteristics of wood and produces compressed wood products of high mechanical properties, high dimensional stability and high bonding performance. This process designed for thin wood lamina(<10 mm). Softening, densification and fixation of wood can be accomplished in a device that can maintain a sealed environment of high temperature with saturated steam. This process only takes around 20 min and the adopted temperature is 150 to 200℃, the production cycle is reduced and the thermal degradation of cellulose is avoided. Compressed lamina can be bonded with other veneer and produce a new wood-based composite product. It can be used for interior, furniture and construction. This article reviews the procedure, device and research status of this technology and analyzes the utilization of compressed wood. In addition, some suggestions about the research direction are proposed.

To evaluate the effects of ectomycorrhizal colonization on nutrient elements of Masson pine(Pinus massoniana) seedlings grown in acidified soils, we grew Masson pine seedlings with Pisolithus tinctorius (ECM) for 210 days in acidified forest soil collected from Chongqing, Southwest China. Three acid levels were set, that is, pH3.5, pH4.5 and pH5.6(served as the control), and two ectomycorrhizal treatments (inoculated, non-inoculated) were conducted. The results showed that: 1) Compared with CK treatment, both acidic treatments decreased soil pH. The pH4.5 treatment had no effect on exchangeable Ca and cation exchangeable capacity (CEC), but increased the content of exchangeable Mg. The pH3.5 treatment significantly reduced exchangeable Ca, Mg and CEC. Inoculation with ECM increased soil pH, exchangeable Ca, Mg and CEC. 2) The acid treatments had no effect on soil organic matter and available K, however they significantly reduced the available P and N content in the soil. Inoculation with ECM under pH3.5 treatment increased soil available P and K content than the non-inocultaion treatment. 3) Acid rain treatments increased N content of needles, and decreased P, K, Ca, and Mg content of needles. Inoculation with ECM reduced N content of needles, and increased P, K, Ca, and Mg content of needles. 4) Acid rain treatments decreased P, K, and Mg content of roots, however inoculation with ECM increased these elements contents, and reduced Al content of roots. These results indicated that inoculation with ECM could effectively alleviate acid rain stress, increase soil buffer capacity to acid rain, decrease Al poison, and increase nutrient absorption capacity and nutrient balance of plants.

The ‘Huazhong 3' is a new variety of Eucommia ulmoides, female plants. It was bred through selection of superior tree, evaluation of afforestation test and regional trail. The variety had characteristics of fast growing, stable high yields, and strong stress resistance. It was suitable for all E.ulmoides distribution regions, particularly for arid and saline areas, to construct orchard for samara harvest, and fast-growing and high-yielding forest for harvesting E. ulmoides barks.